http://www.kellymom.com/bf/pumping/milkstorage.htmlIs she freezing separate bottles of 2-3 oz, and then mixing? Or mixing bm from several pumping sessions, and then freezing the whole amount?
Pumping 2-3 oz, freezing, then pumping 2-3 oz freezing - then thawing and mixing together is fine.
If mixing milk from more than one pumping session before freezing, make sure all the milk is chilled to the same temperature before combining.
Personally, I like to recommend freezing milk in smaller amounts rather than large bags of 6-8 oz. If you freeze bags containing 3-4 oz, you can offer one to baby. If he's still hungry you can give another, but if not, you won't be wasting any bm.